Diplotaxis sahariensis (Coss.) Martínez-Laborde

Martínez-Laborde, Juan B., 2018, Taxa related to Diplotaxis virgata (Brassicaceae) in northwest Africa, Phytotaxa 371 (3), pp. 205-216 : 209-210

Diplotaxis sahariensis (Coss.) Martínez-Laborde , comb. & stat. nov.

Basionym:— Diplotaxis virgata f. sahariensis Cosson (1887: 165) .

Lectotype (designated here):— ALGERIA. Province Naâma: Plaine entre Tyout [Tiout] et Asla , 10 May 1856, Kralik s.n., Herb. Bourgeau, Pl. d’Algérie 1856, n. 241b (lectotype G, right-most specimen!; isolectotypes K!, MPU!, P!).

≡ Diplotaxis cossoniana var. sahariensis (Coss.) Maire (1939: 330) .

≡ D. virgata var. cavanillesiana f. platystylos Nègre (1960: 63) , nom. superfl.

≡ D. virgata subsp. sahariensis (Coss.) Martínez-Laborde (1988: 315 , unpublished; Gómez-Campo 1990: 22, comb. inval.).

Annuals, 15–40 cm tall. Stems erect, foliose, ± pilose with dense, patent to slightly retrorse, rather soft hairs ± 0.5–1.0(– 1.5) mm long, apically less pilose to glabrescent. Leaves ± pilose, hairs patent; basal leaves up to 15 cm long, petiolate, blade oblong-elliptic or obovate in outline, sinuate, dentate or lobate to deeply pinnatisect, with 2–5 pairs of oblong to ovate, ± dentate lateral segments, the terminal segment larger; cauline leaves similar, smaller, with narrower lateral segments, the uppermost cauline leaves elliptic to oblong, attenuate, dentate to somewhat lobate at base. Racemes sometimes bracteate at base. Sepals 3.5–5.3 × 1.0– 1.8 mm, usually dense pilose with rather soft, mostly patent hairs 0.5–1.0(–2) mm long, median sepals slightly cucullate. Petals (6–)7.5–9.5(–10) × (3–)4.0– 5.8 mm, yellow, limb oblong to slightly obovate or suborbicular, claw 2–4 mm long, distinct. Median stamens 5.5–7.0 mm long, lateral stamens 4–5 mm long, anthers 1.2–2.0 mm long. Ovary with (32–)40–70(–80) ovules per locule. Fruiting pedicels (5–)8–11(–16) mm, mostly patent, hairy to glabrescent. Siliques (14–)20–30(–38) × 1.0–1.7(–2.3) mm, suberect to erect-patent, linear-oblong, ± flattened, valves sometimes hairy; carpophore (0.1–) 0.3–0.5 mm; stylar segment (0.5–)1.2–3.0(–3.7) × 0.8–1.3(–1.6) mm (equivalent to approximately 1/20–1/10 of the total length of the silique), frequently attenuate, 1- to 3-veined, containing 1 seed (or aborted ovule); stigma ± capitate. Seeds in 2 rows per locule, 0.6–0.7·× 0.5–0.6 mm, ovoid, ellipsoid or subglobose.

Distribution and habitat: — Diplotaxis sahariensis is endemic to southern and southeastern Morocco south of the High Atlas (Regions Drâa-Tafilalet and Oriental) and northwestern Algeria (Provinces Béchar and Naâma). It is known to grow at elevations between 800 and 900 m above sea level.

Additional specimens examined:— ALGERIA. Province Béchar: Béni Ounif, 1906, Herb. Battandier s.n. ( MPU). Province Naâma: “Duveyrier” [currently Zoubia], 10April 1938, Bertram s.n. ( G, MPU) ; de Mograr [Moghrar] à Djenien bou Resg [Djeniene Bourezg], 16 April 1888, Bonnet & Maury s.n. ( MPU) ; plaine argilo-sablonneuse entre Tyout [Tiout] et Asla, 9 May 1856, Cosson s.n. ( MPU, P) ; ibidem, 11 May 1856, Cosson s.n. ( MPU) ; ibidem, Kralik 11590 ( BM) ; ibidem, 4 April 1875, Warion s.n. ( P) . MOROCCO. Region Drâa-Tafilalet: Erfoud-Alnif , stony desert, 800–900 m, 20 February 1968, Holliday 1a ( BM) ; Erfoud , 27 April 1939, P. & J. Davis 580 ( E) ; Erfoud, at Bordj-Est, 5 April 1969, Davis 49131 ( BM, E) ; Erfoud , 1 May 1927, Maire s.n. ( MPU) ; Ouarzazate , 6 June 1936, Balls B 2640 ( K) ; Zagora , 4 May 1986, Martínez-Laborde 327 ( MA 01-00916875 ) ; Agdz, 850 m, 7 March 1992, Flügel M 38 & D-34593 ( B). Region Oriental: Djahifat , April 1913, Pitard 3065 ( P) ; Djebel Grouz, Pitard 3064 ( P) ; Djebel Melias, Pitard 3069 ( P) ; Djebel Ouazzani, April 1913, Pitard 3063 ( BM, K, P) ; Figuig, April 1924, Humbert s.n. ( P). Region unknown: Aïne Yalau, Pitard 3066 ( P) ; Djebel el Hainer, April 1913, Pitard 3068 ( K, P) ; Sidi Youcef, March 1913, Pitard 3067 ( K, P). Specimens obtained from cultivated material . SPAIN. Madrid: Ciudad Universitaria, spring 1985, Martínez-Laborde 202, culta ex semina BGV-UPM 5550 ( MA 488554 ) ; ibidem, spring 1985, Martínez-Laborde 203, culta ex semina BGV-UPM 5545 ( MA 488555 ) ; ibidem, spring 1985, Martínez-Laborde 204, culta ex semina BGV-UPM 5552 ( MA 488556 ) .

Cultivated material:—BGV-UPM 5550, BGV-UPM 5552, BGV-UPM 5545, BGV-UPM 7515.

Observations: —Two groups of populations close to D. virgata growing farther south and east had been preliminarily distinguished by Martínez-Laborde & Gómez-Campo (1993). In southeastern Morocco and adjacent areas of northwestern Algeria south of Oran one finds plants with rather long, patent but soft hairs and siliques with relatively short stylar segments, which could be identified as D. virgata f. sahariensis Cosson (1887: 165) and are here proposed to constitute a separate species.

Note 1: —As the name of a new taxon, D. virgata var. cavanillesiana f. platystylos Nègre should be considered invalid, since the short descriptive phrase in the key is written in French. However, the phrase “ D. virgata f. sahariensis Coss. , comp., II, p. 165” written just below Nègre’s name constitutes a full reference to a previously published diagnosis with its own valid name, of which f. platystylos should be considered a superfluous synonym, despite the fact that the abundant material cited by Nègre includes specimens belonging not only to D. sahariensis , but also to D. virgata subsp. tenuirostris , and to the new species described further below.

Note 2: —At least eight out of 13 specimens cited under D. virgata var. cavanillesiana f. hispida Nègre (1960: 64) belong to D. sahariensis . However, in the diagnostic French phrase the hairs are described as “raides” (rigid) whereas they are in fact soft. Other specimens belonging to D. sahariensis are cited by Nègre (1960) under his f. platystylos .

Note 3: — Diplotaxis sahariensis belongs to sect. Rhynchocarpum.